This invention relates to acidic electroplating baths, and more specifically to a novel surfactant component for use therein.
In past years, some of the most widely accepted commercial electroplating baths have utilized a cyanide electrolyte. While such baths were highly effective for the electrodeposition of various metals, such also presented significant problems, not the least of which was the toxicity and difficulty of waste disposal unless expensive waste treatment equipment was employed.
To overcome many of the objectionable features of cyanide-based baths, sulfate or chloride electrolytes were proposed, as disclosed, for example, for zinc electroplating baths in U.S. Pat. Nos. 3,729,394; 3,594,291; 3,694,330; and 3,855,085.
In acidic electroplating baths, it is conventional to utilize a surfactant therein to control properties of the metallic deposit, and to assist in solubilizing other organic components. Many such surfactants are commercially available polyethylene oxide-based materials, and as such typically contain a hydrophilic and hydrophobic portion within their chemical structure. The hydrophobic portion of the surfactant, typically an aliphatic hydrocarbon, is undesirable as it can cause problems relative to the metallic deposit, such as blistering, discoloration upon heating, and a reduction in ductility.
While it would be desirable to eliminate the unwanted hydrophobic portion from the surfactant, and possibly replace same with more desirable functional groups, such has not heretofore been available.
It has now been observed that surfactants exhibiting superior properties over previously commercially available materials can be prepared to avoid the aforementioned problems relative to the metallic deposit.